Because of their desirable qualities in terms of magnetic and other properties, amorphous alloys are currently used in magnetic heads in audio and video tape recorders, and the scope of their application is expected to expand in the years to come. Another advantage of amorphous alloys is low iron loss, and thus they can desirably replace silicon steel sheets used in transformer cores, another factor that will contribute to the rapid increase in the volume of amorphous metals to be used in the future. An amorphous metal that holds much promise for use in the core of a transformer is a relatively inexpensive Fe-B-Si base alloy containing boron and silicon in respective amounts of approximately 3% and 5% by weight, based on the total weight.
The conventional processes for the production of amorphous metals are basically the same, comprising an iron source mixed with alloy materials such as Fe-B and Fe-Si to give the desired composition being melted and then quenched rapidly. However, this approach is not ideal for the purpose of obtaining amorphous products of consistent quality, since it often involves great deviations from the intended alloy composition.
In order to replace silicon steel sheets used in the transformer core, amorphous metals have to be produced at a cost higher than about 1.5 times the cost for the production of silicon steel sheets, and such requires, for one thing, the use of an inexpensive mother alloy. However, if a commercial, rather expensive Fe-B is used as a mother alloy, the price of the final product becomes so high as to make commercial production practically impossible.